Gas Turbine Rotor Assembly with Annular Flange Coupling
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Solution Overview
Problem
Current coupling configurations for outer rotor blades in gas turbine engines, particularly those made from composite materials, are challenging due to the need for forming mounting features like holes and slots, which are time-consuming and difficult to create, and result in a shorter service life.
Innovation Solution
A rotor assembly design that uses annular flanges positioned between first and second annular drum segments to secure outer rotor blades, eliminating the need for mounting features on the drum and simplifying the drum structure, thereby increasing service life and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mounting features (holes, slots) are formed on the outer drum to couple blades, then the blades can be secured to the drum, but the manufacturing complexity and time increase significantly
Solution Approach 1:
The outer rotor is divided into a drum portion and a separate coupling portion (flange or disc). The coupling portion is designed specifically to receive and secure the blades, while the drum portion maintains its simple cylindrical structure. This segmentation allows the coupling mechanism to be optimized independently from the drum structure, reducing the complexity of mounting features on the drum itself.
Solution Approach 2:
A separate coupling portion (flange or disc) acts as an intermediary between the drum and the blades. This intermediary component provides the mounting features and coupling mechanism, eliminating the need to form complex features directly on the drum. The coupling portion can be attached to the drum through simpler means such as welding or mechanical fastening.
2Reliability
If mounting features are formed on the outer drum, then blades can be coupled, but the service life of the drum decreases
Solution Approach 1:
By separating the drum structure from the coupling function through segmentation, the drum itself does not require mounting features. The coupling portion bears the stress and wear from blade attachment, preserving the drum's structural integrity and extending its service life.
Solution Approach 2:
The coupling portion serves as an intermediary that protects the drum from direct mechanical stress and wear associated with blade mounting. All loading and wear occur at the coupling portion rather than the drum, thereby extending drum service life.
3Weight of moving object
If the outer rotor drum is made thinner to reduce weight, then weight decreases, but the structural strength and durability are compromised
Solution Approach 1:
The segmentation of the outer rotor into drum and coupling portion allows the drum to be optimized for minimal weight while the coupling portion provides the necessary structural strength for blade attachment. The drum can be made thinner since it no longer needs to bear the mechanical loads of blade mounting.
Solution Approach 2:
The coupling portion acts as a structural intermediary that bears the mechanical loads from blade attachment, allowing the drum to be designed as a thin-walled structure optimized for minimal weight. The coupling portion absorbs all stress concentrations, enabling the drum thickness to be reduced without compromising overall structural strength.
Data Source
AI summary
A rotor assembly for a gas turbine engine includes a shaft and first and second annular drum segments coupled to the shaft. Furthermore, the rotor assembly includes an annular flange positioned between the first and second annular drum segments along the axial centerline, with the annular flange coupled to the first and second annular outer drum segments. Additionally, the rotor assembly includes a blade having a shank section and an airfoil section. The shank section is, in turn, coupled to the annular flange such the airfoil section extends inward along the radial direction toward the axial centerline and into a hot gas path of the gas turbine engine.